Power weapons are a type of advanced hand-to-hand combat weapon taking several forms but utilising the same basic technological principles. When activated the blade of the weapon becomes sheathed in a field of energy which disrupts solid matter, allowing the weapon to easily tear through armour, including even Terminator Armour.

The basic power weapon type (commonly taking the shape of swords and axes) is in use by several races including humans, while specialized types see more exclusive use.

Relic Blade[12]: A large, two-handed power sword, glaive or axe that were specially crafted (often during the Horus Heresy) to give a strength bonus that, while not as powerful as that of a power fist, allows the user to strike at normal speed.

Astartes Power Spear[16]: A power weapon that requires two hands to use and is rarely seen amongst the Space Marines of the Deathwatch. Some Space Marines of the Iron Snakes Chapter have donated these weapons to the armoury of Watch Fortress Erioch.

The Sword of Heironymo: An exceptionally strong power sword, and an heirloom of the city of Vervunhive on Verghast. It is said that whoever leads Vervunhive's forces in battle must wield this weapon. After the death of most of Vervunhive's leadership - military and administrative - during Heritor Asphodel's invasion in 769.M41, the sword was given to Colonel-Commissar Ibram Gaunt, the senior Imperial commander in Vervunhive (all of the others either dead or imprisoned). The sword remained in Gaunt's possession after the battle, gifted to him for his actions in the defence of Vervunhive during the Heritor's siege. A deadly weapon, it has never left Gaunt's side[19].